These filters typically have a blue hue to them as they also sometimes block some of the light from the longer red wavelengths.

Birds, however, can see some red wavelengths, but not as many as humans.

As a result, when the particle is dropped out of focus the red wavelengths are focused inward.

To make a photo-like satellite image, you need red, green, and blue wavelengths of light.

If red wavelengths are removed, the light will appear 'green', and the opposite way too.

A red wavelength was mainly of interest in America.

"The color from the pen absorbs and blocks the red wavelengths of light."

For example, a blue light filter appears blue because it absorbs red and green wavelengths.

The photoreceptors for red and far-red wavelengths are known as phytochromes.

Behind the gauge body are light sources with two quite different wavelengths, typically red and green.